fix(archive): kind cross-check on definition-ref label resolution

[braghettos]

What

Hardening follow-up to #24. Step 1 of searchCompositionDefinition (definition-ref label resolution) trusted the instance's composition-definition-name/-namespace labels blindly — no kind cross-check. If those labels ever pointed at a CompositionDefinition of a different kind (mislabeled instance, or name reuse after a delete/recreate), step 1 would resolve — and fetch — the wrong chart.

The guard

After finding the CD by name+namespace in step 1, verify its status.kind equals the instance kind (via the existing getChartVersionKind helper; its version return is ignored, and an error reading the status kind is treated as a mismatch):

• Match → use it (current behavior, unchanged).
• Mismatch → log a Warn (refName/refNamespace, expected kind, found kind) and fall through to step 2 (exact version+kind match) — the mislabeled CD is neither used nor turned into an error, so the later fallbacks can still resolve the true owner.

The stale-label path (ref labels matching no CD at all) keeps its existing Debug log and fall-through.

Test

New table case in getter_search_test.go: instance ref-labels point at an existing CD whose status.kind differs → resolution falls through and succeeds via the exact version+kind match on the true owner. All 7 cases pass:

--- PASS: TestSearchCompositionDefinition
    --- PASS: .../definition-ref_labels_win_despite_version_skew_and_same-kind_ambiguity
    --- PASS: .../exact_version+kind_match_still_works_without_ref_labels
    --- PASS: .../stale_ref_labels_fall_through_to_exact_version_match
    --- PASS: .../ref_labels_pointing_at_a_different-kind_definition_fall_through_to_exact_match
    --- PASS: .../unique-kind_fallback_tolerates_version_skew_without_ref_labels
    --- PASS: .../ambiguous_same-kind_definitions_with_version_skew_still_error
    --- PASS: .../single_definition_fast_path_unchanged

gofmt clean, go build ./... and go test ./internal/tools/archive/... pass.

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